<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<p>
    <button onclick="alert(123)">按钮1</button>
</p>
<script !src="">
    //const oBtn = document.querySelector('button');
    //oBtn.onclick = ()=>{
    //
    //}
</script>
</body>
</html>